Process of making white lead.



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lillj 'll/IIEE EUETUN, UF ST. LGUIS, MISSOURI, ASSIGNUR T0 EUSTON LEAD COMPANY, OF

LOUIS, MISSOURI, A. CQRPORATION OF MISSOURI.

PROCESS OF MAKING LEAD.

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No Drawing.

Specification of Letters Patent.

Application filed September 1, 1910. Serial No. 580,020.

Iatcnted Septfi, 1911.

To all coho mi may concern:

llc i't'lijnownthat I, EDWIN EUs'roN, a citizen of the United States, residing at lliouiskllfissouri, have invented a certain I and useful Improvement in Processes of aking l'flllte Lead, of which the following a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same This invention of white lead.

The object of th invention is to provide a process of converting light, flu'fiy, overcarbonated lead of approximately the formula 3PbC/U PbO H, into white lead of the theo- .:ally correct formula ZPbCG PbO H ll all the physical qualities of the lead now manufactured.

Various so-callcd quick processes have heretofore been attempted in the manufacture of white lead, but such processes have not proved entirely satisfactory from a .commercial standpoint owingto the fact that they produced a light, fiufiy, over-carbonated lead which required considerably more linseed oil to form a paint than perfect white lead of the composition QPbC() ,.PbO,H and which was inferior in other respects as a pigment to perfect white lead.

l have discovered that the excess of carbon dioxid can be removed from such overcarbonated lead to produce white lead of the composition EfPbCO Pb O H similar in all respects to the best white lead produced by any method of manufacture. Various means can be used for removing this excess of carbon dioxid, such, for example, as treat relates to the manufacture ing the over-carbonated lead with a solution of neutral acetate of lead of the character-.

istic acid reaction, or with a dilute mixture of water and acetic or other acid, such as nitric or sulfuric acid, it being desirable, however, to use an acid which forms soluble lead salts, which are readily removed from the white lead by washing.

The over-carbonated lead being treated 18 agitated by any suitable meanswith a suilicient amount of acetate of lead solution or a ably shoiv an acid reaction throughout the treatment, dilute acetic acid being added in small quantities during the process, when necessary. Or, if acetic or other acid and water are used, an amount of acid suilicient to obtain the desired result is used, usually 1% to 2% of the weight of lead treated being suflicient. The acid and water are preferably mixed together before being brought into contact with the lead, and additional amounts of dilute acid may be added during the treatment of the lead, if found necessary.

The products of the-so-called quick proccsses and also the products sometimes produced by the old Dutch process, which are over-carbonated, can be converted into perfect white lean by my improved process.

Having thus described the invention, What is claimed as new and desired to be secured by Letters Patent is:

l. A process of converting over-carbonated lead into commercial white lead, which consists insubjecting over-carbonated lead to the action of an acid solution and agitating it.

2. A process'of converting light, flufly, over-carbonated lead into commercial white lead of the chemical composition which'consists in treating the lead With asolution of neutral acetate of lead of acid reaction and agitatingit.

In witness whereof I hereunto aflix my signature in the presence of two witnesses, this twenty-ninth day of August, 1910.

EDWIN EUSTON. 

